Investigations are being conducted into the biochemical composition of the sensory retina, pigmented epithelium and choroid in normal and disease states, particularly in animal models of human retinal degenerations and diseased human ocular tissues. The tissue specific distributions of inorganic constituents are studied by flameless atomic absorption, with concentrations of Ca, Cu and Zn of particular interest. The effects of nutrition and genetic background on the progress of chorioretinal degeneration in the retinal dystrophic pigmented RCS rat and of cataract formation and prevention in the tan-hooded pink-eyed retinal model for human retinitis pigmentosa is being investigated, including use of genetic linkage studies to attempt to identify a RCS-like human disease. Diabetic rodents are being followed for the development of retinal disease that may model human diabetic retinopathy.